Otto p



UNITED STATES PATENT OFFICE.

' OTTO P. AMEND, OF NEW YORK, N. Y.

PROCESS OF DYEING ANlLlN BLACK.

SPECIFICATION forming part of Letters Patent No. 499,410, dated June 13, 1893.

Application filed November 18.

To all whom it may concern:

Be it known that I, OTTO P. AMEND, a citizen of the United States, and a resident of the city of New York, State of New York, have invented a certain new and useful Process of Producing a Fast-Black Color on Fibrous Substances, of which the following is a specification.

I-Ieretofore processes of printing or dyeing in black upon vegetable fibers, as cotton, linen and mixed fibers, with aniline, toluidine and other aromatic amines and their salts, have produced fairly satifactory results, but all attempts to produce a fast black with such amines and salts upon animal fibers, especially wool and silk, have proved unsuccessful. Various processes have been tried, but none has produced a fast black. These failures have been attributed by some to a peculiar reducing action of the fibers during the dyeing or developing of the black, and as the processes have depended upon oxidation of the dyeing material to produce the color this contemplated oxidizing eifect has been counteracted by the reducing action of the animal fibers. Others attribute these failures to the peculiar action of the fibers due to thesulphur contained in them, and various processes have been devised for a partial or complete elimination of this sulphur, but all such processes have so far proved unsuccessful.

I have found that an aqueous solution of chromic acid in presence of another acid that will not produce a secondary oxidizing re-aotion on the fiber, preferably hydrochloric or acetic acid, produces upon animal fibers a peculiar and very intimate union and combination, whereby the fiber is partially oxidized and part of the chromic acid is taken up by it and apparently combines with it, forming a chromic compound with the fibers. It is necessary that the quantity of chromic acid in the solution be such that after a part is reduced to chromic oxide, a sufficient amount remains to combine with the fiber. The presence of the second acid is necessary to keep in solution all of the chromic oxide formed and thus prevent its being deposited on the fiber. The acids which cannot be used in the solution with the chromic acid are such acids 1892. Serial No.462A39. (N0 specimens.)

and the development is finally completed at a. heat of about 80 centigrade.

My new process is applicable to wool, silk and other animal fibers and also to vegetable fibers, and may be applied to such fibers in any'of their usual forms, as when in a sepa rated state, or when twisted into yarns or threads or when woven into cloths or other fabrics.

I will now fully and particularly describe my complete process.

I prepare an aqueous solution of chromic acid and hydrochloric acid and immerse the woolorother fabric therein. The proportions of acid for each one half kilogram of wool,

are about twenty grams of anhydrous chromic acid and about thirty grams of hydrochloric acid. Sufficient Water is employed to permit complete immersion of the fiber therein. The solution is used at ordinary room temperature, from 20 to 30 centigrade. After the above described treatment the excess of the solution is removed from the fiber by suitable mechanical means, such as wringing or pressing through rollers. The second solution is composed of aniline, toluidine or other aromatic amine or its salts which will produce black and of metallic oxide salt, in the proportion for every one half kilogram of wool or other fiber, of about fifty grams of the arematic amine or salt and proportionate amount of the metallic oxide salt. 0f the latter substances I have found that ferric sulphate produces very good results. Sufficient water is employed to completely immerse the fiber. The solution is used at ordinary room temperature. After immersion in this second solution, the color begins to develop at the ordinary room temperature.

After a certain 10o shade has been produced, the excess of the solution is mechanically removed, and the material is subjected to a temperature of about 80 centigrade. This may be accomplished by placing the substance within a so-called Mather & Platt steam box or other heating device.

' It will of course be understood that my invention is not limited to the exact proportions above specified. For instance, the amounts of chromic acid and of hydrochloric acid above specified may be considerably exceeded without other result than a waste of such acids. So also some fibrous substances may require slightly diiterent proportions of the various aromatic amines, salts, and acids. Nor are the exact temperatures above described always essential to my invention. A beautiful deep black coloris produced. The material as thus colored will be found to withstand all the tests required of the best and most expensive blacks known. The fiber will be found to have lost none of its original physical properties, but on thecontrary to have gained increased strength.

Having thus described my invention, what I claim as new, and desire to secure by Letters Patent, is-

1. The process of producing a fast black color on fibrous substances, which consists in treating such substances with a solution of on the fibers and then treating such substances with a solution containing an aromatic amine or its salt, substantially as set forth.

2. The process of producing a fast black color on fibrous substances, which consists in treating such substances with a solution of chromic acid in presence of other acid, that will not produce a secondary oxidizing eifect on the fibers and then treating such substances with a solution of an aromatic amino or salt with a salt of metallic oxide, substantially as set forth.

3. The process of producing a fast black color on fibrous substances, which consists in treating such substances with a solution of chromic acid in presence of another acid or acids, that will not produce a secondary oxidizing effect on the fibers then removing excess of said solution, then treating such substances with a solution of an aromatic amine or salt with a salt of metallic oxide, then permitting the black to partly develop at ordinary room temperature, then removing excess of said solution,then subjecting such substances to a higher temperature whereby such ;color is completely developed, substantially as set forth.

OTTO P. AMEND.

\Vitnesses:

HENRY D. WILLIAMs, ROBT. A. KELLAND. 

